What is knowledge? by AC Grayling

Since Plato one of the central questions in all human enquiry has been: what is knowledge and how do we get it? Almost every philosopher who has discussed the question agrees that knowledge is more than belief – ‘believing’ is a psychological state, and we can believe things that are false and even impossible, whereas ‘knowing’ is a relation between the psychological state of believing and something external to it, something which is actually the case and which thus makes the belief true. But even this is not yet enough to turn a belief into knowledge: for not only must the belief be true in virtue of something other than itself, but the believer must have a justification – which means: a very good and secure reason – for regarding his or her belief as true. This gives us the familiar definition of knowledge as ‘justified true belief.’

But this definition raises key questions. What is truth? That is a very important question for another time. And: what is justification? Might it not happen that we seem to have the best justification for believing something, and still be wrong? This is what skeptical arguments force us to consider, arguments such as Descartes’ ‘evil demon’ considerations or arguments based on undeniable facts about our human propensity to perceptual and reasoning error. When we begin to examine ways of countering or avoiding skeptical arguments we realise that different fields of enquiry, and different kinds of experience, require that we think about the acquisition and verification of knowledge in a variety of ways.

Consider the difference between getting knowledge in the natural sciences and getting knowledge in other areas of enquiry such as sociology or history. In the natural sciences we talk about forming hypotheses and testing them by experiment, so we raise questions about experimental methodology, the nature of evidence, the ‘defeasibility’ of scientific knowledge (that is, the fact that it is open to correction or refutation by future evidence), the status of theoretical entities such as protons and electrons, and more. The ideal in natural science is the public, repeatable testing of hypotheses by experiment. By contrast, in other areas of enquiry such as those social sciences dealing with unique, subjective and transient psychological or sociological phenomena – which therefore cannot be inspected in a laboratory – or in the study of history where evidence is so often fragmentary and ambiguous, different techniques of enquiry have to apply. This shows that the key idea of ‘justification’ might have to be understood in different ways depending on subject matter; and each such way must itself be satisfactorily explained.

It is a significant fact that debate about the nature of knowledge and the best means of getting it was revived by Descartes in the early seventeenth century just at the time that modern science was beginning. For many centuries beforehand, the human mind was in thrall to the idea of ‘authority’ – the authority of ancient philosophers such as Aristotle, or of the teachings of the church, or of the ruling elites in society. The beginning of modern times, which historians of ideas date to the sixteenth and seventeenth centuries, is marked by the refusal to accept what conventional authorities said, but instead to seek knowledge in independent-minded ways – to look, think, experiment, test, reason and enquire without preconceptions. Only then did it again become important to ask ‘what is knowledge?’ after a long period of time in which supposed authorities said, ‘Don’t ask questions; we (the people in charge) know the answers already.’ As this shows, enquiry into the nature of knowledge is a mark of freedom of mind – which in turn is a precondition for finding out anything of value about ourselves and the world.

A C Grayling MA, DPhil (Oxon) FRSL, FRSA is Master of the New College of the Humanities, and a Supernumerary Fellow of St Anne’s College, Oxford. Until 2011 he was Professor of Philosophy at Birkbeck College, University of London. He has written and edited over thirty books on philosophy and other subjects; among his most recent are “The Good Book”, “Ideas That Matter”, “Liberty in the Age of Terror” and “To Set Prometheus Free”. For several years he wrote the “Last Word” column for the Guardian newspaper and a column for the Times. He is a frequent contributor to the Literary Review, Observer, Independent on Sunday, Times Literary Supplement, Index on Censorship and New Statesman, and is an equally frequent broadcaster on BBC Radios 4, 3 and the World Service. He writes the “Thinking Read” column for the Barnes and Noble Review in New York, is the Editor of Online Review London, and a Contributing Editor of Prospect magazine. In addition he sits on the editorial boards of several academic journals, and for nearly ten years was the Honorary Secretary of the principal British philosophical association, the Aristotelian Society. He is a past chairman of June Fourth, a human rights group concerned with China, and is a representative to the UN Human Rights Council for the International Humanist and Ethical Union. He is a Vice President of the British Humanist Association, the Patron of the United Kingdom Armed Forces Humanist Association, a patron of Dignity in Dying, and an Honorary Associate of the National Secular Society. Anthony Grayling was a Fellow of the World Economic Forum for several years, and a member of its C-100 group on relations between the West and the Islamic world. He has served as a Trustee of the London Library and a board member of the Society of Authors. He is a Fellow of the Royal Society of Literature and a Fellow of the Royal Society of Arts. In 2003 he was a Man Booker Prize judge, in 2010 was a judge of the Art Fund prize, and in 2011 the Wellcome Book Prize. He is the chairman of the 2014 Man Booker Prize. He supports a number of charities including Plan UK, Greenpeace, Médecins Sans Frontières, Amnesty International and Freedom from Torture. He is also a sponsor of Rogbonko School in Sierra Leone. Anthony Grayling’s latest books are “The God Argument” (March 2013) and “Friendship” (September 2013).